f_old = open('old.txt','w+')
f_old.write('这是原文件')
f_old.close()


f_old_r = open('old.txt','r+')
f_flag = f_old_r.read()

f_new = open('new.txt','w+')
f_new.write(f_flag)

f_old_r.close()
f_new.close()